Stimw
Elite Member
For the OP, a good source to check out is Surplus Center who is also a sponsor on this site and has great prices!
Hydraulics/wheel motor question
- Thread starter curtjeep
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4570Man
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I'd try to find a junked skid steer. You'd get most of the needed components at a cheap price.
I didn't think about a skid steere. That would give me the pumps I need. And a size for the wheel motors.
Stimw- I have already bookmarked a few items from surplus center.
Stimw- I have already bookmarked a few items from surplus center.
4570Man
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It'll give you pumps, valves, 2 drive motors enough cylinders for your loader, and an engine. You could probably make do with the 2 drive motors. You can use 2 truck rear ends and drive each one with your drive motors. Then if you had 4 independent brakes that's pretty much the same thing as traction control.
After looking at the cadtrac I have decided I will definitely build my own. The only thing I'm worried about is getting the correct size wheel motors. I am going to ride on the rear and the steering will use a power steering arm from a vehicle in a junkyard. With a shaft with heim joints at both ends to articulate the two halves. I will run two pumps off of the motor shaft. Probably 8gpm a piece unless I need more flow on the wheel motors. So, question for the experts, what size wheel motors do I need to look for. I will probably run either a 23 or 26" tire and I am looking for roughly 5 mph that way I have a decent amout of torque. I want to stay relatively cheap on the wheel motors if possible, but am not going to go cheap and have them wear out or not run the machine.
MossRoad
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Go over to the Power Trac forum and ask that question. There's a couple guys that replaced their wheel motors with larger displacement motors for lower spee/higher torque.
Also, you'll be sorry if you go with one steering arm from a vehicle. Go with two steering rams, one on each side. Trust me, you'll be sorry if you don't. Really sorry. It'll be weak if you go that route. And you'll find the forces of push and pull under load between two articulating sections will be really hard. Remember, that steering will have to twist as well. Car steering doesn't twist.
Check out the dual steering rams on the PT design. The rams have the heim-type joints on each end as well. The whole thing is super flexible.
Also, you'll be sorry if you go with one steering arm from a vehicle. Go with two steering rams, one on each side. Trust me, you'll be sorry if you don't. Really sorry. It'll be weak if you go that route. And you'll find the forces of push and pull under load between two articulating sections will be really hard. Remember, that steering will have to twist as well. Car steering doesn't twist.
Check out the dual steering rams on the PT design. The rams have the heim-type joints on each end as well. The whole thing is super flexible.
MossRoad
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If you use truck differentials, you're going to end up with a tall machine on tall tires to get ground clearance for the differentials. And a short, stubby machine with high ground clearance AND ARTICULATION will be a tippy machine with a high center of gravity.
Something to note about articulating machines. The center of gravity changes DRASTICALLY as you turn. That's because the machine gets shorter as you turn the steering wheel, and longer as you straighten it back out.
We, on the Power Trac forum call this the PT Pucker! Because you don't expect it until you experience it. Fill the bucket with a heavy load and turn the wheel to the left and the right rear tire will come off the ground. Straighten out the wheel and the right rear will come back to earth. Do that on a hillside and you'll understand where the pucker factor comes in.....
MossRoad
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Power Tracs don't have any sheet metal. All plate steel.
MossRoad
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As for brakes.... none of the Power Tracs have brakes, so to speak. That's the beauty of all hydraulic drive. You let off the go pedal and the machine stops. They have parking brakes. And the larger ones have a brake tender. It has to build hydraulic pressure before the brakes release. But there are no brake pedals at all.
